Characterization of Pixel Defect Development During Digital Imager Lifetime

The reliability of solid-state image sensors is limited by the development of defects, particularly hot-pixels, which we have previously shown develop continuously over the sensor lifetime. Our statistical analysis based on the distribution and development date of defects concluded that defects are not caused by single traumatic incident or material failure, but rather by an external process such as radiation. This paper describes an automated process for extracting defect temporal growth data, thereby enabling a very wide sample of cameras to be examined and studied. The algorithm utilizes Bayesian statistics to determine the presence and absence of defects by searching through sets of color photographs. Monte Carlo simulations on a set of images taken at 0.06 to 0.5sec exposures demonstrated that our tracing algorithm is able to pinpoint the defect development date for all the identified hot pixels within ±2 images. Although a previous study has shown that in-field defects are isolated from each other, image processing functions applied by cameras such as the demosaicing algorithm were found to cause a single defective pixel to appear as a cluster in a color image, increasing the challenge of pinpointing the exact location of hot defects